Thailand | Area code 66 | Common abbreviation THA | Last updated 10-6-2006 | |||
| Road class | Syntax explanation | Administrative subordination | Sub classes | Zones | System | Remarks |
| Asian highway | A[0-9]<1-2> | Asia | See Asia | |||
| National road | [0-9]<1-4> | national | 1-d | spider-web | ||
| 2-d | 1 Northwest (area around highway 1) 2 Northeast (area around highway 2) 3 Centre (area around Bangkok) 4 South (area around southern part of highway 4) | |||||
| 3-d | ||||||
| 4-d | ||||||
| General description: Zones are determined by the first digit of each number. The class distiniction is not very strict: an important main road can have a 3-digit number. In general, however, higher numbers tend to have shorter routes than lower numbers. | ||||||
| Road signs: Asian highway numbers are rarely indicated. Signs are usually in Thai and English. | ||||||
| Road/destination type | Background | Text | Road numbers | |||
| Background | Text | |||||
| To motorways | Blue | White | Blue | White | ||
| On motorways | Green | White | ||||
| Main roads | White | Black | ||||
| Local roads | White | Black | ||||
| History: Recently some new numbers have been introduced that do not fit the system (e.g number 9 is a ring road around Bangkok). | ||||||
Sources: various maps and atlases; Thomas Kneissl
Official sites: Other links: | ||||||